1. Field of the Invention
The present invention relates to an air float bar for use in positioning, drying or curing of a continuous planar flexible material such as a web, printed web, news print, film material, or plastic sheet. The present invention more particularly, pertains to an air float bar whose pressure pad area includes an ultraviolet bulb, a reflector surface and a lens to enhance accelerated ultraviolet heating of a web material to cause solvent evaporation, drying or curing. Electromagnetic ultraviolet heat energy in combination with columns of heated air impinging upon the web surface provides for concentrated heating of the web material thereby providing subsequent rapid evaporation, drying or curing from the surface of the material.
2. Description of the Prior Art
Demand for increased production volume and production speed of web material in dryers has caused the printing industry to increase web speed on their printing lines. Typically this speed-up requirement resultant in the dryer being inadequate in drying the web, because the web did not remain in the dryer adjacent to a series of air bars for a sufficient length of time to dry the web because of the increase web speed. The solution for adequate drying was to either replace the entire dryer with a longer dryer, or to add additional drying zones in series with a first dryer zone. This, of course, is expensive and ofter times not feasible due to a shortage of physical floor space.
The present invention overcomes the disadvantages of the prior art dryers by providing an ultraviolet air float bar to replace existing air float bars in web dryers. In addition to air flow of dry air from the Coanda air flow slots at the upper and outer extremities of the air float bar, an ultraviolet bulb, including a reflector and a lens, positioned between the Coanda air flow slots, transmits ultraviolet electromagnetic radiation to the traversing web. The transversing web drying is accomplished by impingement of a combination of both heated Coanda air flow and ultraviolet electromagnetic radiation. The combined concentration of heat from the Coanda air flow and the ultraviolet electromagnetic radiation from the ultraviolet bulb is of a sufficient magnitude which allows the web to dry at a higher speed than normal prior art speed.